Is this Sony's new waterproof Z1 smartphone?

Sony's new Z1 smartphone might just be the worst-kept secret at this year's IFA electronics show in Berlin.

The annual consumer electronics showcase doesn't properly get under way until Thursday, but details of the phone have already leaked across various smartphone blogs.

And then, on Tuesday night at the Sony Center, in the heart of Berlin, four female models danced on a stage in front of a camera crew, interrupting their dance with brief pauses so their picture could be taken with a smartphone. At the center of the stage was a large, transparent half-globe of warm water into which two of the models submerged themselves—and the phones.

The models swam under the water with the phone and sometimes paused again, this time to take photos of each other with the phone.

Nick Barber, IDGNS

The new Z1 is reported to be waterproof. What better way for Sony to show off the feature at its news conference on Wednesday than with an artistic video shot just meters from its European headquarters building?

Officials on scene wouldn't confirm what phone was being showcased, but the location and presence of at least one photographer wearing a Sony Alpha shirt points toward it being Sony's new flagship Android smartphone. Alpha is a brand used by Sony for its high-end digital cameras.

Sony is expected to unveil the Z1 at a news conference planned for 6 a.m. PDT on Wednesday.